Electric shutter blade actuating device for a photographing apparatus

ABSTRACT

In the disclosed electric blade actuating device for a photographing apparatus an electromagnetic mechanism has a bladeactuator frame with at least three magnets, a stationary supporting member and electromagnetic coils or solenoids in numbers corresponding to the number of said magnets, and a switching means for said electromagnetic mechanism. The electromagnetic coils or solenoids are fixedly provided on said stationary supporting member. The switching means is arranged to switch the feed polarity from a power source to the electromagnetic mechanism for blade actuation by rotating the actuator frame. This is done by exciting the electromagnetic coils. The electromagnetic mechanism is arranged on a circumference of the device about equal intervals.

atent Unite States Mizui et al.

1451 Aug. 29, 1.972

v[72] Inventors: Seiichiro Yoshiyuki Takishima, Kawasaki,

[54] ELECTRIC SHUTTER BLADE ACTUATINGDEVICE FOR A PHOTOGRAPHING APPARATUS Mizui, Yokohama;

4 21' Appl No.: 33,542

30 Foreign Application Priority Data May 10, 1969' Japan ..44/42497 52 us. CL... ..95/53 EA,-95/63, 95/64 B 51 Int. (:1. ..G03b- 9/22, G03b 9/07 [58] Field of Search.....95/'10 c, 53 E, 53 EA, 53 EB, 95/58, 4 R, 64 B, 63

[56] I References Cited UNITED STATES PATENTS 3,466,993 9/1969 Fahlenberg et a1.........-...95/ 63 3,092,002 6/1963 Frenk... ..95/58 3,547,021 12/1970 Pross ..95/53 EA 2,973,699 3/1961 Nerwin ..95/10 0 3,295,428 1/1967 Nerwin .......95/64 1,444,365 2/1923 Bowes ..95/53 E x FOREIGN PATENTS OR APPLICATIONS 37/l0285 8/1962 Japan ..9'5/6413 Primary Examiner-Joseph F. Peters Attorney-McGleW and Toren 57 ABSTRACT In the disclosed electric blade actuating device for a photographing apparatus an electromagnetic mechanism has a blade-actuator frame with at least three magnets, a stationary supporting member and electromagnetic coils or solenoids in numbers corresponding to the number of said magnets, and a switching means for said electromagnetic mechanism. The electromagnetic coils or solenoids are fixedly provided on said stationary supporting member. The switching means is'arranged to switch the feed polarity from a power source to the electromagnetic mechanism for blade actuation by rotating the actuator frame. This is done by exciting the electromagnetic coils. The electromagnetic mechanism'is arranged on a circumference of the device about equal intervals.

12 Claims, 5 Drawing Figures PRESET DIAPHRAGM MECHANISM Patented Aug. 29, 1972 3,687,042

2 Sheets-Sheet l PRESET DIAPHRAGM MECHANISM INVENTOR SEIKIH'Ro HILUI Yosmuln Tmnsnmn BY w eewfiTm ATTORNEY Patented Aug. 29, 1972 3,687,042

2 Sheets-Sheet 2 INVENTOR. ssueuma HI'LMI Yosmvum Tnmsumn Ju ah as 7.7m.

ELECTRIC SHUTTER BLADE ACTUATING DEVICE FOR A PHOTOGRAPHING APPARATUS The present invention relates to an improvement in electric blade actuating device for photographic apparatus.

The ideaof constructing an electric blade actuating device for an electrically preset diaphragm disclosed in Japanese Patent Publication Sho 37-10285, published Aug. 4, 1962. It was expected in the above patent publication that remote control of the device would become easybecause the connection between an electromagnetic mechanism for blade actuating provided in a camera and "a blade control device such as a diaphragm blade control device is achieved by providing lead wires in the device. Also the device disclosed inthe above patentpublication was expected to be advantageous for blade actuation in a single lens reflex camera with interchangeable objectives.

Recently the demand for enhancing the performance of interchangeable objectives has increased. Also the application of electronics to a camera has become common. Thus use of the device as disclosed in the prior art has increased. On the other hand, when an electric bladeactuatingdevice for preset diaphragm is to be incorporated intoan interchangeable objective having a longer focal distance, it becomes difficult to attain a necessary diaphragm accuracy with aconventionally used mechanically linked system. The present invention is intended to meet such recent demands as mentioned.

Therefore,one of .the objects of the present invention isto provide an electric blade actuating device for a photographing apparatus which is operable in a simplified linked manner and is easy to separate, and furthermore has a good dynamic balance and excellent starting and stopping characteristics.

The present invention provides an electric blade actuating device fora photographing apparatus comprising an electromagnetic mechanism having a blade-actuator frame with at least three permanent magnets, a stationary supporting member and electromagnetic coils or solenoids in numbers corresponding to the number of said magnets, and a switching means for said electromagnetic mechanism, said electromagnetic coils or solenoids being fixedly provided on said stationary supporting member, said switching means being arranged to switch the feed polarity from a power source to said electromagnetic mechanism for blade actuation by rotating said actuator frame through exciting the electromagnetic coils, and said electromagnetic mechanism being arranged on a circumference of the device with above same intervals. The feature of the present invention assure a good dynamic balance at the time of blade actuation by means of the electromagnetic mechanisms. Excellent starting and stopping characteristics are attained through the use of the switching means. Furthermore power consumption is reduced because a pulse of power with a reverse polarity supplied through the switching means causes the blade actuator frame to return to its original position.

The presentinvention shall be described in detail with reference to the drawings in which the blade actuator frame serves only to actuate the diaphragm blades. However, the device according to the present invention serves to actuate only shutter blades or serves to actuate blades for both shutter and diaphragm functions.

In the attached drawings;

FIG. 1, FIG. 2, FIG. 3 are schematic drawings showing the relationship between an actuator frame and stators in an electric blade actuating device for a photographing apparatus according to the present invention.

FIG. 4 and FIG. 5 are schematic diagrams showing control circuits for electricity supply from a power source to the stators. 1

In FIGS. 1-3, 1 shows a blade actuator frame, 2 are coils or solenoids fixedly provided on a stationary supportingmember (not shown in the drawings) in an interchangeable objective or in a camera body or in a camera. The frame 1 actuates a plurality of blades B, only one of which is shown. The apparatus shown in FIGS.. 1, '2- and 3 cooperate with a pre-setting mechanism PM in a single lens reflex camera SLR, which are shown schematically. Each of the solenoids comprises a coil and an iron core A provided therein.

Magnets positionedat S and N are integrally combined with the blade actuator frame. The coils or solenoids are arranged in an angular direction, in a radial direction, and in an axial direction parallel to the optical axis of an objective as shown in FIGS. 1,. 2, and 3 respectively. Each of the coils or solenoids is so arranged that the feed polarity to it may bereversed. The

coils or solenoids and the blade actuator frame constitute an electromagnetic mechanism. which serves as an adder at one position and serves as a subtractor due to a mutual inductance between the coils or solenoids and the frame. Although the cumulative function and the differentional function are attained by the switching means, it is also possible to construct the device so as to bias the diaphragm actuating frame by means of a spring to return to the maximum aperture side when photographing is not made.

Next, explanation follows on the reversing of feed polarity for each of the coils or solenoids 2 in the electromagnetic mechanisms for driving the actuating frame.

In FIG. 4, 3 is a capacitor connected to a feed circuit and 4 is a polarity-reversing switch. The switch 4 in FIG. 4 has two interconnected switching elements. The switch 4 in FIG. 5 has one switching element. The switch 4'is maintained in an off state at a stage of shutter ready. When a shutter button is pressed down the switch is brought to a state that the blade actuator frame is actuated in one direction to close the diaphragm. In this stage, the frame with magnets is held, for example, by the iron core, and the power supply to the coils" or solenoids 2 is interrupted so as to reduce the power consumption. After the closure of the shutter, the switch 4 is connected to the power source with a reverse polarity to open the diaphragm. When the diaphragm is opened, the switch 4 is turned off to a condition corresponding to the state of shutter ready so as to reduce the power consumption. Similar mechanisms as described above are applicable to actuate a shutter. In this case the switch 4 must be related to a delay device for delaying switching action from a terminal to another terminal. In this embodiment the starting and stopping characteristics of the electromagnetic mechanism is improved. In reversing the feed polarity to motor by the switch 4, transistor circuits shown in FIG. may be used, and in this case the capacitor may be omitted. 5 is an electromagnet mechanism.

.In a single lens reflex camera, the polarity reversing switch may be arranged so as to link itself with the swing of a reflex mirror. Combination of the device with a conventional diaphragm presetting mechanism provides an excellent system for a single lens reflex camera.

Three or more coils or solenoids are arranged on the circumference of the device with almost equal intervals and the magnets in number corresponding to the number of the coils or solenoids are provided on the blade actuating frame. Thus the device is smoothly driven with a good dynamic balance, and thus the opening and closing operation of the diaphragm is accomplished very smoothly.

What is claimed is:

1. An electric blade actuating device for a photographing apparatus comprising an electromagnetic mechanism having a blade-actuator frame with at least three permanent magnets, a stationary supporting member and electromagnetic coils in numbers corresponding to the number of said magnets, and switching means for said electromagnetic mechanism, said electromagnetic coils being fixedly provided on said stationary supporting member, said switching means being arranged to switch the feed polarity to said electromagnetic mechanism so as to rotate said actuator frame by exciting the electromagnetic coils, said electromagnetic coils being arranged circumferentially about the frame at substantially equal intervals.

2. An electric blade actuating device according to claim 1 which further comprises iron cores in numbers corresponding to the number of the magnets.

3. An electric blade actuating device according to claim 2 in which said iron cores are arranged inside the coils.

4. An electric blade actuating device according to claim 2 in which the frame is actuatedin one direction" by a pulse of power from a power source supplied through the switching means and is held at one position with mutual inductance between the permanent magnets and the cores and the frame is returned in the other direction by a pulse of power with a reverse polarity supplied through the switching means and is held at its original position with 'mutual inductance between the permanent magnets and the cores.

5. An electric blade actuating device according to claim 1 which further comprises a capacitor in the switching means for improving starting characteristics of the electromagnetic mechanism.-

6. An electric blade actuating device according to claim 1 in which the switching means comprises a semiconductor for inverting the polarity of a power supply.

7. An electric blade actuating device according to claim l in which the blade actuator frame actuates shutter blades.

8. An electric blade actuating device according to claim 1 in which the blade actuator frame actuates diaphragm blades.

9. An electric blade actuating device according to 'glai' 8 in which the device is combined a lap r ns re ex agm presetting mechanism in a single le camera.

10. A device as in claim 1 wherein said frame is circular, said electromagnetic coils are mounted with axes extending peripherally about said frame, and said permanent magnets project peripherally about said frame and along the axes of said coils.

11. A device as in claim-1 wherein said frame is circular and wherein said coils have axes arranged radially relative to said frame.

12. A device as in claim 1 wherein said frame is circular and wherein said coils have axes parallel to the axis of the circular frame.

UNITED STATES PATENT OFFICE CERTIFICATE OF CGRECTIQN Patent NO. Dated August 9 l t fl Seiichiro Mizui and Yoshiyuki Takishima It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the heading of the patent the name of the assignee should read- Canon Kabushiki Kaisha Signed and sealed this 3rd day of Apri1'1973.

(SEAL) Attest: v EDWARD M.PLETCHER,JR. I v ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents FORM 301050 (069) USCOMM-DC eoa7e-pa9 11.5. GOVERNMENT PRINTING OFF-CE I969 O365'33A.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent NO. 3, 7, Dated August 9, 972

I t Seiichir'o Mizui and Yoshiyuki Takishima It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the heading of the patent the name of the assignee should read Canon Kabushiki Kaisha Signed and sealed this 3rd day of April 19-73.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents FORM PO-IOSO (10-69) USCOMM DC 6O376 p59 r us GOVERNMENT PRINTING ornca: 1959 o-ass-su, 

1. An electric blade actuating device for a photographing apparatus comprising an electromagnetic mechanism having a bladeactuator frame with at least three permanent magnets, a stationary supporting member and electromagnetic coils in numbers corresponding to the number of said magnets, and switching means for said electromagnetic mechanism, said electromagnetic coils being fixedly provided on said stationary supporting member, said switching means being arranged to switch the feed polarity to said electromagnetic mechanism so as to rotate said actuator frame by exciting the electromagnetic coils, said electromagnetic coils being arranged circumferentially about the frame at substantially equal intervals.
 2. An electric blade actuating device according to claim 1 which further comprises iron cores in numbers corresponding to the number of the magnets.
 3. An electric blade actuating device according to claim 2 in which said iron cores are arranged inside the coils.
 4. An electric blade actuating device according to claim 2 in which the frame is actuated in one direction by a pulse of power from a power source supplied through the switching means and is held at one position with mutual inductance between the permanent magnets and the cores and the frame is returned in the other direction by a pulse of power with a reverse polarity supplied through the switching means and is held at its original position with mutual inductance between the permanent magnets and the cores.
 5. An electric blade actuating device according to claim 1 which further comprises a capacitor in the switching means for improving starting characteristics of the electromagnetic mechanism.
 6. An electric blade actuating device according to claim 1 in which the switching means comprises a semiconductor for inverting the polarity of a power supply.
 7. An electric blade actuating device according to claim 1 in which the blade actuator frame actuates shutter blades.
 8. An electric blade actuating device according to claim 1 in which the blade actuator frame actuates diaphragm blades.
 9. An electric blade actuating device according to claim 8 in which the device is combined with a diaphragm presetting mechanism in a single lens reflex camera.
 10. A device as in claim 1 wherein said frame is circular, said electromagnetic coils are mounted with axes extending peripherally about said frame, and said permanent magnets project peripherally about said frame and along the axes of said coils.
 11. A device as in claim 1 wherein said frame is circular and wherein said coils have axes arranged radially relative to said frame.
 12. A device as in claim 1 wherein said frame is circular and wherein said coils have axes parallel to the axis of the circular frame. 